It's just kind of a play on words in your case. An oxymoron is like, for example, "stupid genius", so when he or she is saying universally relative, they are using big fancy words that are supposed to mean a whole lot, but that in reality don't mean anything at all (worth of the oxymoron) because he using using two contradictory words in conjunction. Hence, his words are completely meaningless.
O así parece para mi.